Click here for the rules  
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To the Fairly Difficult 7x7 Number Maze. To the ChangingRule Number Maze. Further notes: This maze and the 7x7 Number Maze both use the same set of rules. These rules are not an original invention of mine; in fact, mazes with these rules are now something of a tradition. The layouts of these two mazes, however, are original. As far as I can tell, the earliest use of these rules was in Sam Loyd’s puzzle “Back from the Klondike,” first published in Loyd’s newspaper column in 1898. I would guess that Loyd invented these rules, though you can never be sure about these things. You can find Loyd’s puzzle in Mathematical Puzzles of Sam Loyd, edited by Martin Gardner. I highly recommend that book, as well as Gardner’s follow up, More Mathematical Puzzles of Sam Loyd. I do not, however, recommend “Back from the Klondike.” It’s much too complicated. It uses a huge grid of 325 numbers. Loyd used the puzzle as a contest in the newspaper, and he made it overly complex so he wouldn’t get too many correct entries. The number mazes presented here are copyright © 1999 by Robert Abbott. If you are interested in programming these mazes for a different device (PDA, cell phone, video game controller), please see my terms of use.
